US3367399A - Continuous casting apparatus - Google Patents

Description

Feb. 6, 1968 R. EASTON 3,367,399

CONTINUOUS CASTING APPARATUS Filed June 16, 1965 I NVENTOR. RUFUS E145 TON United States Patent f 3,367,399 CONTINUOUS CASTING APPARATUS Rufus Easton, Pittsburgh, Pa., assignor to Koppers Company, Inc., a corporation of Delaware Filed June 16, 1965, Ser. No. 464,285 13 Claims. (Cl. 164-282) ABSTRACT OF THE DISCLOSURE Apparatus for producing continuous cast strands of steel includes an arcuate apron structure that supports and guides the strand along a curved path lying in the vertical plane of the casting mold and subtending a first angle greater than 90 lying on one side of the strand, and then along a continuation of the curved path in the same vertical plane that subtends a second angle less than 90; the angles lying on opposite sides of the strand.

This invention relates to continuous metal casting and, more particularly, to improvements in the method and apparatus for continuous casting of steel.

The continuous casting of metals, and steel in particular, has usually been carried out by flowing molten metal into a vertical casting mold from which a continuous strand of cast metal is withdrawn vertically downward, and cut in the vertical position into the lengths required. This requires high structures. Some casting machines have bent the casting through 90 degrees after complete solidification, or in some cases even before complete solidification, restraightening at ground level, with considerable saving in height.

In the present invention, the casting, which is continuously withdrawn from a continuous casting mold, is supported on and guided by an arcuate apron structure disposed adjacently beneath the mold. The supporting roller apron structure guides the casting through an arc of substantially more than 90 and then reverse-curves the casting in the opposite direction through an angle substantially less than 90'; both angles lying substantially in the vertical plane of the casting. The vertically disposed mold may have either curved or parallel sides.

For a further understanding of the present invention and for further advantages and features thereof, reference may be made to the following description taken in conjunction with the accompanying drawing which shows, for the purpose of exemplification, embodiments of the invention.

In the drawing:

FIG. 1 is a schematic elevational View, partly in section, of one type of continuous casting machine including the present invention; and

FIG. 2 is a schematic elevational view, partly in section, of another type of continuous casting machine including the present invention.

Referring to FIG. 1, the continuous casting mold 11 is positioned above a ground or support level 13. The molten metal 15 enters a conventional tundish 17 from a conventional ladle 19 and discharges into the vertical planar walled cavity of mold 11. While not shown, the mold 11 may be oscillated vertically in the usual manner to prevent the casting from sticking to the walls of the mold. A continuous cast strand 21 is formed within the mold 11 and while it is being formed, it is withdrawn and supported upon a curved roller apron structure 23.

, 3,367,399 Patented Feb. 6, 1968 "ice The apron structure 23 includes a plurality of groups of rollers 25 disposed generally on opposite sides of the casting, and opposed groups of spray nozzles 27 are arranged intermediate the groups of rollers 25 in the usual manner.

In accordance with this invention, the rollers 25 are disposed generally along concentric arcuate axes 29, 31 which subtend an angle 28 greater than Preferably, as shown in FIG. 1, the axes 29, 31 of the rollers 25, and the arcuate axis of the cast strand 21 subtends an angle 28 that is approximtaely Thereafter, the axis 34 of the strand 21 is substantially straight for a short distance 32, in the region between A and B, as shown in FIG. 1. As illustrated in FIG. 1, the portion 32 of the casting is inclined upwardly at an angle of approximately 45 to the horizontal or ground level 13; however, this angular upward inclination may be varied with any particular installation.

In the region between B and C, as shown in FIG. 1, the curvature of the axes 34 of the strand 21 and 29, 31 of the rollers, is reversed. Preferably, both the arcuate apron axes 2?, 31, and the arcuate cast billet axis 21, in the region between B and C subtend an angle substantially less than 9'0", and preferably about 45 Thereafter, from the location marked C, the axis of the cast strand is substantially horizontal. The strand 21 enters a unit 33 which operates both as a pinch roll to control the movement of the casting and as a straightener device to straighten the casting in a horizontal position. A conventional cut-off apparatus 35, which may be either a shears or a torch mechanism sever the strand 21 into individual billets, such as the billet 37, which are conveyed hence in a conventional manner on a usual runout conveyor 39.

It is convenient and preferable to support the casting mold 11 and the pinch roll-straightener unit 33 at nearly the same level, if possible. This can be practically accomplished by supporting the unit 33 substantially at ground level 13, and by providing a pit or sump 41 in the ground adjacent to the unit 33 in which the lower portion of the arcuate roller apron structure 23 'is mounted. The mold 11 can then be mounted vertically above the apron structure and only slightly above the elevation of the unit 33.

FIG. 2 illustrates the invention in association with a casting mold 43 which has an arcuate mold cavity wherein a curved continuous cast strand 45 is formed by molten metal 47 discharging from a tundish 49; the molten metal 47 discharging into the tundish from a conventional ladle 51.

In this embodiment, the continuous cast strand 45 is also supported on an arcuate roller structure 53 which is associated with groups of conventional type spray nozzles 55, and as such is similar to the apron structure 23 described hereinbefore. The continuous cast strand 45 is bent in a vertical plane in such a manner that its axis 57, subtending an angle that is greater than 90, continues between A and B in a substantially straight line that inclines upwardly from a horizontal ground or support level 59 at an angle of approximately 45. Between the region B and C, the curvature of the cast strand 45 is reversed in a manner whereby, when the strand leaves the region C, it enters a unit 61 that is similar to the unit 33 which operates both as a pinch roll to control the movement of the casting through the machine and as a straightening device to straighten the casting. The casting 45 then passes by a cut-off device 63 by means of which the strand is severed to form billets, one of which is illustrated at 65. The billets 65 are carried thence on a conventional runout table 67 as mentioned previously.

In the embodiment of FIG. 2, the lower portion of the apron structure 53 is preferably disposed and supported in a pit or sump 69 in the ground 59, in the manner described hereinbetore.

It should be understood that in some installations there may not be a substantially straight portion in the region between A and B. After the casting 21 has been curved in one direction, it may thereafter be curved in a reversed manner substantially continuously. That is to say, the axis of the cast strand forms a continuous smooth reversing or S-shaped curve in the region between A and C. In this case, the region B is coincident with the region A and reverse curvature exists between A and C. This situation may obtain in either or both of the embodiments of FIG. 1 and FIG. 2.

It will be appreciated by those skilled in the art that by virtue of using the curved continuous casting mold 43, the height of the mold above the support or ground level 59 is considerably less than the embodiment of FIG. 1. In such an installation, the mold 43 may be at, or even just slightly below, the level of the unit 61, as illustrated in FIG. 2.

While the invention has been described in relation to embodiments in FIGS. 1 and 2, showing an arcuate apron structure that guides the continuous cast strand in an are substantially greater than 90 after it leaves the continuous casting mold, it should be understood that the casting may be formed in accordance with the teachings in my co-pending application, Continuous Metal Casting Method and Apparatus, Serial No. 404,236, filed October 16, 1964, now Patent 3,329,199.

In operation of the apparatus of this invention, the molten metal is fed into the mold from the ladle 19 and the tundish 17 in the customary manner. The continuous cast strand 21 is started in the usual manner by using a dummy bar (not shown) to close the bottom of the flow-through casting mold 11 and to withdraw the strand from the mold in a continuous manner. Such a dummy bar may be of the flexible type as shown and described in Patent 2,920,359. The cast strand 21 will be shaped to the curvature of the mold (with vertical planar sides of FIG. 1, and with curved sides in the embodiment of FIG. 2) and upon emerging from the mold, will be supported upon the arcuate apron structure 23.

When the continuous cast strand 21 emerges from the pinch roll-straightener unit 33, it is substantially straight and is in a substantially horizontal position. Thereafter, the strand passes by a conventional cut-off device, such as a shears or torch mechanism, and the strand is severed into billets of preselected length. Such billets, of course, are supported on the usual run-out table and conveyed thereby to other locations.

The use of continuous casting machines in older types of melt shops has been uneconomical because the vertical type of casting machine heretofore available, required so much head room that they could not be installed within the existing facility. The present invention, however, includes a low-head continuous casting machine that overcomes this objection. The continuous casting machine embodying the present invention may be readily and conveniently installed in practically any existing melt shop, simply by excavating a pit or sump and installing therein the lower portion of the arcuate type of apron structure in the manner illustrated schematically in FIG. 1 and FIG. 2.

That continuous casting machines embodying the present invention have many economical features and advantages should be evident to those skilled in the art. Although the foregoing describes, with a certain degree of particularity, preferred embodiments of the invention by way of an example, it is understood that the invention 4 is not so limited, but is defined by what is hereinafter claimed.

I claim:

1. A continuous metal casting machine comprising:

(a) a ladle for containing molten steel;

(b) a tundish for receiving and discharging therefrom said molten steel;

(0) a vertically reciprocable flow-through casting mold having a cavity therein wherein a continuous cast strand is formable when said molten steel is discharged from said tundish into said cavity;

(cl) an apron structure disposed adacently below said mold for supporting the casting emerging from the mold, one portion of said apron structure being for supporting a curved cast strand subtending an angle greater than and another portion of said apron structure being for supporting said strand in an arc subtending an angle that is substantially less than 90, the centers of curvature of said arcs being coplanar and on opposite sides of said strand;

(e) spray means for cooling said strand as it emerges from said mold and while it is supported by said apron structure;

(f) apparatus operatively engaging said strand for controlling the movement thereof through said machine and straightening said strand;

(g) means for severing into billets said continuous strand after it emerges from said control apparatus; and

(h) means to remove said billets from adjacent said machine.

2. A continuous casting machine comprising in combination:

(a) a ladle containing molten steel;

(b) a tundish for receiving and discharging therefrom said molten steel;

(0) a vertically reciprocable flow-through casting mold having therein a cavity wherein a continuous cast strand is formable when said molten steel is discharged from said tundish into said cavity;

(d) means for continuously withdrawing said strand from said mold;

(e) a structure disposed adjacently below said mold for supporting said casting after it emerges from said mold and before it enters said withdrawing mechanism, said structure being for supporting the curved strand in a substantially vertical plane and in such a manner that one portion of said strand subtends an angle greater than 90 and an adjacent portion of said strand subtends an angle substantially less than 90, said angles being on opposite sides of said strand and in said vertical plane; and

(f) spray means for cooling said strand while it is supported on said structure.

3. In a continuous casting machine the combination comprising:

(a) a vertically reciprocable flow-through casting mold having therein a cavity wherein a continuous cast strand is formable from molten steel continuously flowing into said cavity;

(b) a structure disposed adjacently below said mold for supporting said strand after it emerges from said mold and before it enters said withdrawing mechanism, said structure being for supporting the strand in a substantially vertical plane and in such a manner that one portion of said strand subtends an angle greater than 90 and an adjacent portion of said strand subtends an angle substantially less than 90, said angles being on opposite sides of said strand and in said vertical plane; and

(c) means to cool said strand after it emerges from said mold.

4. A continuous casting machine comprising:

(a) a vertically reciprocable flow-through casting mold supported above a first level wherein a continuous cast strand is formable by pouring thereinto molten steel;

(b) apparatus supported at a second lower lever between said mold level and said first level and operaand in said vertical plane; and

(b) means to cool said strand while it is supported on said apron structure.

6. In a continuous casting machine the combination angle substantially greater than 90 and so that the axis of a second portion of said strand subtends an angle substantially less than 90, said angles being on opposite sides of said strand and in said vertical tively engaging said strand .for controlling the plane; withdrawal movement thereof through said machine (e) means for supporting said apron structure at a level and for straightening said strand; below said casting mold with the first portion of said (c) an apron structure disposed adjacently below said casting being substantially tangent to a level that is casting mold for supporting said casting in the region below the level at which said casting is discharged between said mold and said control apparatus, said m from said machine; and structure including means for supporting the curved (f) spray means for cooling said strand upon emerging strand in a substantially vertical plane and in such a from said mold. manner that one portion of said strand subtends an 9. The invention set forth in claim 8 wherein: angle greater than 90 and an adjacent portion of (a) the tangent level of said first portion of said strand said strand subtends an angle substantially less than is below said ground level. 90, said angles being on opposite sides of said strand 10. A continuous strand casting apparatus comprising: and in said vertical plane; and (a) a substantially vertical flow-through casting mold ((1) means to cool said strand after the same emerges adapted to retain molten steel and form therein a from said mold. continuous cast strand; 5. In a continuous casting machine including a substan- (b) first means to continuously withdraw said strand tially vertical casting mold and a strand withdrawal appafrom said mold; ratus, an apron structure comprising: (c) second means for supporting said continuous (a) a plurality of groups of rollers arranged adjacently strand with the path of travel of said strand being to said casting mold for supporting said strand exin a substantially vertical plane and a first portion of tending in a vertical plane between said mold and the cast strand subtending a first angle substantially said strand withdrawal apparatus, in such a manner greater than 90 and an adjacent portion of said cast that one portion of said strand subtends an angle substrand subtending a second angle, oppositely disposed stantially greater than 90 and an adjacent portion of to said first angle, that is substantially less than 90 said strand subtends an angle substantially less than and with the first portion of said cast strand being 90, said angles being on opposite sides of said strand 3 substantially tangent to a level that is below the level of both the mold and the strand withdrawal means; and

((1) means to cool said strand while it is supported on said second means.

11. In a continuous casting machine including a substantially vertical casting mold and a strand Withdrawal apparatus, an apron structure comprising:

including: (a) a vertically reciprocable flow-through casting mold supported above a first ground level wherein a continous cast strand is forma'ble by pouring thereinto molten steel;

(b) an apron structure for supporting said casting after the same has emerged from said mold, said apron structure comprising a plurality of groups of rollers adapted to maintain the axis of said cast strand in a substantially vertical plane and in such a manner that the axis of a first portion of said strand subtends an (a) a plurality of groups of rollers adjacent said casting mold for supporting said casting extending in a vertical plane between said mold and said casting withdrawal apparatus in such a manner that one portion of said strand arcuately subtends an angle greater than 90 and another spaced apart portion of said casting arcuately subtends an angle less than 90, said angles being on opposite sides of said cast angle Substantially greater than 90 and so that the strand in said vertical plane, with the portion of said axis of a second portion of said strand subtends an casting between said arcuate portions extending upangle substantially less than 90, said angles being wardly f m a horizontal level; and on opposite sides of said strand and in said vertical (b) a plurality f spray nozzles located near said plane; and rollers from which cooling fluid emerges to contact (c) means for sup p or Said. apron smicture at a and cool said strand as it emerges from said mold.

Second level below Said castmg mold Wlth the first 12 In a continuous casting machine the combination portion of said casting being substantially tangent to inclugiing 2121,5 ,;f iififi ffi fjifi i 22 5 sald castmg (a) a vertically reciprocable flow-through casting mold (d) means for cooling said strand as it emerges from Supported a first level a,contlnuous said mold. cast strand is formable by pourmg thereinto molten 7. The invention set forth in claim 6 wherein: steel; (a) the tangent level of said first portion of said strand a plurality of groups Tone? adlacent 531d P is below said ground level. for supporting said casting exiting therefrom in a 8. A continuous casting machine comprising: vertical plane, and in such a manner that a first pora ladle adapted to Contain molten Steel; tion of said strand arcuately subtends an angle a illndish adapted t0 receive and discharge thefegreater than 90 and a second spaced apart portion of from Said molten Steel; the strand arcuately subtends an angle less than 90, a Vertically reciprocable flow-through Casting mold said angles being on opposite sides of said cast strand having a cavity therein wilerein a continuous F in said vertical plane and with the portion of said Str.and formgble when molten Steel flows Into casting between said arcuate portions extending uplsaldlcavity, said mold belng supported above a first ward from a horizontal level;

eve (d) an apron structure for supporting said casting after 7 (6) ,means coolmg Sald Strand upon exmng from the same has emerged from said mold, said apron Bald mold Structure comprising a plurality of groups of rollers (d) means to withdraw said strand continuously from for maintaining the axis of said cast strand in a sub- 531d P stantially vertical plane and in such a manner that 13- The lIlVeIltlOIl Set fOfth 1n a m 1 2 wh r lni the axis of a first portion of said strand subtends an 7 (a) said first portion of said strand IS substantially 8 tangent to a level below the level of sa id withdrawal OTHER'REFERENCES meansv Ref Cited I r Continuous Casting of Steel, Special Report 89, Percy, Lund, Humphries and CO. Ltd., LOl'ldOIl 2,698,467 1/1955 Tarquinee et a1. 16489 5 and 2,920,359 V1960 Easton et a1 X Handbook des strangglessens, Alummum Yerlag 2,947,075- 8/ 1960 Schneckenburger et a1.v GmbH, 1958, TS230H47, pp. 450-451.

. 164-283 X 5 31157920 -11/1964 Hess 164 282 X 10 J. SPENCER OVERHOLSER, Primary Examiner,

FOREIGN PATENTS J AQ EA A t 116,378 1/1943 Australia. 3 S L N 123,117 12/1946 Australia.

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